1. Field of the Invention
The present invention relates to a method and a circuit for simultaneously establishing a number of communication links between a subscriber station, which is connected to a switching center of a communication network via a single subscriber line, and other subscriber stations connected to the same communication network.
2. Description of the Prior Art
In currently existing communication networks, the communication accesses are only designed for producing a single connection in the case of analog accesses and, as a rule, for two communication links which can be established at the same time in the case of digital communication accesses, especially ISDN accesses. Although it is generally possible in ISDN communication networks to allocate a whole series of transmission channels to a subscriber station for simultaneously establishing a corresponding number of links, it must be taken into consideration that this procedure is not available everywhere and, in some cases, is not possible at all from the point of view of switching.
Accordingly, the present invention is directed to a way in which a number of simultaneous communication links are possible between a subscriber station connected to a switching center of a communication network via a single subscriber line and other subscriber stations connected to the same communication network.
According to the present invention, the object indicated above is achieved in a method wherein the subscriber line is operated, between its subscriber station and the associated switching center of the relevant one communication network, as a multiplex line via which a number of communication links to a corresponding number of communication terminals belonging to the subscriber station can be set up, in that at least one junction line is operated as a multiplex junction line between the relevant switching center and a translating device and in that, in the translating device, message signals for various communication links, transmitted in multiplex mode from the one subscriber station via the relevant one switching center, are conducted back in individual links to the switching center from which individual links are then set up to desired subscriber stations to be called, on the one hand, and, on the other hand, message signals intended for the communication terminals of the one subscriber station are accepted in individual links and are then conducted back to the individual communication terminals of the one subscriber station via the relevant switching center in a multiplex link.
The present invention has the advantage that, without any intervention in the switching system to which the one subscriber station is connected, a number of communication links can be simultaneously established between this subscriber station and a number of other subscriber stations connected to the same communication network. The method according to the present invention is, thus, especially well suited to a subsequent increase in the number of communication links which can be simultaneously established between a subscriber station connected to a switching center of a communication network via a single subscriber line and other subscriber stations connected to the same communication network.
The multiplex link is suitably operated as a time-division multiplex link. This has the advantage that the multiplex link can be achieved in a particularly simple manner.
It is of advantage if, when using a digitally operated subscriber line with at least one communication channel which can be used by the relevant subscriber station, this channel is divided into a number of subchannels in the time-division multiplex link.
It is of special advantage in this arrangement if the voice signals to be transmitted in the individual subchannels are transmitted in compressed form. This ensures that there is virtually no reduction in voice quality in the case of a transmission of voice signals.
When a translating device is used in a gateway to another communication network, especially a data network, preferably the Internet, message signals and signaling signals are suitably transmitted to and from the individual terminals of the one subscriber station in the form of data signal packets in the data network. In the case where the relevant data network is formed by the Internet, the transmission techniques practiced in the Internet are thus advantageously applied in said one subscriber station. In the case of voice connections, this is also called xe2x80x9cVoice over IP (Internet Protocol)xe2x80x9d world.
To carry out the method according to the present invention, it is appropriate to use a circuit having at least one subscriber station, which exhibits a number of communication terminals and which is connected to a switching center, especially a digital switching center of a communication network, via a single subscriber line.
According to the present invention, this circuit arrangement is characterized by the fact that the communication terminals provided at the at least one subscriber station are connected at the subscriber end of the subscriber line of the relevant subscriber station via a multiplexer/demultiplexer, that, at that switching center, a translating device having a demultiplexer/multiplexer is connected via at least one junction line, between which demultiplexer/multiplexer and former multiplexer/demultiplexer multiplex links can be set up from and to the communication terminals of the one subscriber station via the switching center and the subscriber line, and that the relevant translating device is also connected to the switching center via a number of individual junction lines via which, on the one hand, message signals supplied in a multiplex link via the junction line can be conducted back to the switching center in individual links, in which or via which switching center the relevant message signals can be forwarded to appropriate subscriber stations to be called and via which switching center, on the other hand, message signals can be conducted in the direction of communication terminals of the one subscriber station in individual links to the translating device, via the demultiplexer/ multiplexer of which these message signals can be transmitted in a multiplex link via the one junction line to the relevant one switching center and via the latter toward the appropriate communication terminals of the relevant subscriber station.
The circuit measures indicated above provide the advantage of a relatively low circuit expenditure overall when the method according to the present invention is carried out. In the switching center to which the one subscriber station is connected via its subscriber line, no circuit changes at all are carried out. Corresponding circuit measures are only taken at the relevant subscriber station and in the translating device.
The translating device is suitably contained in a gateway to another communication network, especially the Internet, in which arrangement communication links, which can be set up or forwarded to or from further subscriber stations connected at the further communication network, at the one switching center or at another switching center of the one communication network, can be set up between the relevant gateway and the subscriber station. This has the advantage that the circuit arrangement according to the present invention can be implemented in a particularly simple manner.
In the case where the further communication network is a data network, especially the Internet, a translating circuit is preferably provided between the multiplexer/demultiplexer and the subscriber line, in which circuit message signals and signaling signals delivered by the relevant subscriber station are translated into data signal packets which can be processed in the data network, and in which circuit data signal packets supplied from the data network are translated into message signals and signaling signals for delivery to the appropriate communication terminals of the subscriber station. This results in the advantage of relatively low circuit expenditure to be able to transmit the signals to be transmitted to and from the one subscriber station effectively in the data network. If the relevant data network is the Internet, the transmission protocols to be used for transmitting the various signals in the Internet can be easily taken into consideration in the aforementioned translating circuit.
It is also of advantage if the multiplexer/demultiplexer is connected to the switching system to which the one subscriber station is connected, via a separate signaling control circuit via which the respective connection setup from the relevant subscriber station via the switching system to the translating device connected thereto can be controlled. As a result, the respective connection setup from the subscriber station to the translating device can be controlled in a particularly simple manner.
Additional features and advantages of the present invention are described in, and will be apparent from, the Detailed Description of the Preferred Embodiments and the Drawings.